Furnace or kiln for roasting ores.



No. 781,904. PATBNTED FEB. 7, 1905. G. 0. PETERSSON.

FURNAGE 0R KILN FOR ROASTING GRES. APPLIUATION FILED DBO. 7, 196s.

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UNITED STATES Patented February 7, 1905.

PATENT OFFICE.

FURNACE OR KlLN FOR ROASTING CRES.

SPECIFICATION forming` part of Letters Patent No. 781,904, datedFebruary '7, 1905.

Application filed December 7,1903. Serial No. 184,241.

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Be it known that I, GUs'rAE OSKAR PETERS- soN, a subject of the King ofSweden and Norway, and a resident of Dalsbruk, in the county of Abo, inthe Grand Duchy of Finland, Russia, have invented certain new and usefulImprovements in Furnaces or Kilns for Roasting Finely-Crushed Ore,Burning Dolomite, Sac., of which the following` is a specification.

T he present furnace or kiln, illustrated in the accompanying' drawingsin a longitudinal section in Fig'ure l, in a cross-section in Fig'. 2,and in plan view in Fig'. 3, consists, essentially, of a shaft a,contracted at the bottom and traversed by a number of arches b c d atdifferent levels, said arches, however crosswise, not extending acrossthe entire shaft, but being arranged alternately at both sides of it, asbest seen from Fig. Q. The space beneath the bottom arch or bottomarches Z) at one end communicates with the outer air through passages e,arranged in one of the abutment-walls of the arch, while the other endof said space is connected with a gas-fire chamber and a chamber f,arranged beside The gas is supplied to the fire-chamber through a pipey. The space beneath the arches c, situated above the arches b,communicates at one end with the chamber f and at the other with achamber 7l, arranged in the opposite abutment-wall and communicating atits upper part with one end of the spacebeneath the arches d. whichspace at the other end communicates with a chamber e', arranged abovethe chamber 7" and connecting' with the chimney which should preferablybe carried through the gas-supply pipe g, so as to admit of heating' thegas. rFhe air used for the combustion of the gas will thus be heated bythe material to be roasted in the lower part of the furnace or kiln asthe air passes to the chamber f, and the products of combustion formedin said chamber subsequently flow back and forth through the material tobe roasted on their way to the chimney. By using several arches andseveral chambers in the walls of the furnace or kiln it is evidentlypossible to compel the gases to pass several times back and forththrough the material to be treated. The capacity of the furnace or kilnevidently can be increased either by making it higher and using' agreater number of arches c (l above one another than is shown in thedrawings or by making' it wider and placing' several arches side by sideor by both these arrangements simultaneously. A good result may also beobtained by using' only one arch c since by making these arches verylarge the furnace or kiln may be made quite eflieient, while it is atthe same time easy to manage on account of the few arches. ',l hematerial to be roasted is fed in at the top either intermittently orcontinuously and is taken out at the bottom orifice of the shaft. Partof it will then in the beginning stop on the arches and remain there;but between the arches a passage will always be formed, through whichthe remainder of the material successively descends, according as thefinal product is drawn off below, and this latter part will be actedupon by the traversing current of gas.

In the walls of the kiln sight and slice holes should be arranged sothat the material to be roasted can be reached in case it should clog.Such holes should likewise be arranged in the end walls of the kilnopposite the apertures beneath the arches c and (Z.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is- An improved furnace or kiln for roasting finely-crushedore, burningdolomite,&c., provided with flat arches 7, c, arranged in ashaft at different levels zigzag' with reference to one another, andhaving a space between themselves and the walls of the shaft and withthe space beneath the bottom arch or arches communicating at one endwith the outer air and at the other end with a lire-chamber which in itsturn communicates with one end of the space beneath the arch or archescabove,\vliile the other end of the latter space is in comn@ 781,90@ y umunication with a chamber it. in its turn communicating With the spacebeneath the top arch or arches d, said space last mentionedcommunicating with a chimney either directly or through the aid of otherarches compelling the gases to HOW repeatedly back and forth in thefurnace 0r kiln.

In Witness whereof I have hereunto Set my hand in presence of twoWrtnesses.

GUSTAF OSKAR PETERSSON.

W'tnesses:

A. KOSTELMAN, W. FAGERLAND.

